Evaluation and selection of indirect ELISA and sandwich ELISA kits for anti-HCV detection

Objective To compare the sensitivity and specificity between indirect enzyme-linked immunosorbent assay ( ELISA) and double-antibody sandwich ELISA kits produced in China and to select the best ELISA kit. Methods Samples for evaluation included 60 serum plates and 40 serum samples positive or weakly positive for antibody to hepatitis C virus ( anti-HCV) which were confirmed by recombinant immunoblot assay. These samples were tested with a sandwich ELISA kit and three indirect ELISA kits, all of which were produced in China. Comparison between ELISA kits was made by paired chi-square test; comparison of false negative rate was made by R ×C contingency table test. Results The sensitivities of three indirect ELISA kits and a sandwich ELISA kit were 90. 2%, 78. 0%, 95. 1%, and 97. 6%, respectively, and the specificities were 78. 1%, 72. 6%, 94. 1%, and 100%, respectively. The sandwich ELISA kit had a 4-8 times higher sensitivity than indirect ELISA kits. The R × C contingency table test revealed significant differences in false negative rate between ELISA kits and combinations of ELISA kits ( χ2= 29. 898, P < 0. 05) . Conclusion Sandwich ELISA kit has higher sensitivity and specificity than indirect ELISA kits. Combined use of sandwich ELISA and indirect ELISA kits can significantly reduce the false negative rate and effectively prevent missed anti-HCV detection.